1. Field of the Invention
The present invention relates generally to log structures and methods of constructing log structures. More particularly, the present invention relates to a log cutting machine and associate process of cutting logs for use in log structure construction.
2. Background of the Invention
In the process of manufacturing log structures, raw logs from felled timber are typically hand selected and sent to the sawmill for processing. At the sawmill, two parallel cuts are made of the raw log to produce a log that is sawn flat on two parallel sides and then left with the natural contour of the original tree (less bark) on the two remaining surfaces. If desired, two further parallel cuts can be made of the log to remove the opposed natural contoured edges, producing a rectangular cant which will form a portion of the log structure. For log structures which specify a more natural looking log, the natural contoured edges are left on the log (or xe2x80x9chalf finishedxe2x80x9d cant).
Before the log can be joined with other logs to form the structure, the log must be further processed. If the log is to be used in the construction of walls, each end of the log is cut with some sort of intersecting notch (i.e., a dovetail). If the log is to be used as a rafter or beam, a bird""s mouth cut may be required. Rectangular logs are typically processed at this point with a large cutting machine, commonly referred to as a joinery machine, which makes the necessary joinery cuts. The straight edges of the rectangular log enable the joinery machine to make the necessary cuts with precision. The same process may be employed by use of simpler machinery operated manually. But, in all cases, the straight edges of the log cant greatly simplify the manufacturing process. Logs which still have the natural external contour of the raw timber log in place on opposed edges of the log cannot be so easily processed because the width of the log will vary along its length. Thus, the joinery cuts must be carefully measured and made by hand, often with chain saws. As compared to the joinery machine or other method of processing a rectangular timber cant, the process of making joinery cuts by hand on an irregularly shaped timber log is labor intensive, expensive, and much more prone to error.
Therefore, there is a need for an improved machine and method of processing logs for use in the construction of log structures.
The present invention eliminates the difficulties and disadvantages of the prior art by providing an apparatus for processing a log to be incorporated into a log structure. The log includes two substantially parallel surfaces, two opposed edges which maintain the natural contour of the raw timber log, and a log centerline. The apparatus includes a support for supporting the log substantially horizontally on one of its substantially parallel surfaces. A cutter is provided for cutting the log. A mover moves the log substantially horizontally along the support to the cutter. A guide aligns the log centerline with respect to the cutter, and a controller is employed for controlling operation of the mover and the cutter.
In accordance with one aspect of the invention, the guide is in the form of a log guide which is attached directly to the log. The log guide includes a guide edge which maintains contact with the fence as the log is moved to the cutter. The log guide also includes a centerline which is aligned with the log centerline when being attached to the log. If desired, two or more of the log guides may be attached to the log.
In accordance with another aspect, the guide is in the form of a fence guide attached to the fence. The fence guide includes a guide edge which maintains contact with the bottom of a guide channel formed in the log at a uniform distance from the log centerline as the log is moved to the cutter. If desired, two or more of the fence guides may be attached to the fence.
In accordance with a further aspect of the invention, the guide includes two opposed alignment elements forming a portion of the mover. The alignment elements are positionable adjacent the opposed, naturally contoured edges of the log and are movable by the controller to clamp the log in compression and to align the log centerline with respect to the cutter.
The present invention also provides an apparatus for processing a log to be incorporated into a log structure where the log includes two substantially parallel surfaces and a log centerline normal to the substantially parallel surfaces. The apparatus includes a support for supporting the log substantially horizontally on one of its substantially parallel surfaces. A fence is positioned adjacent the support. A cutter, such as a saw blade or universal mill, is provided for cutting the log. A mover is used to move the log substantially horizontally along the support to the cutter. A controller, which may be networked to computer aided design workstations, controls operation of the mover and the cutter. The apparatus also includes at least one guide, which is not a portion of the log itself, in contact with the fence. The effect of the guide is to maintain the log centerline substantially parallel to the fence at a fixed distance from the fence as the log is moved to the cutter.
The present invention also provides a method for processing a log to be incorporated into a log structure where the log includes two substantially parallel surfaces and a log centerline normal to the substantially parallel surfaces. In accordance with the method, the log is supported substantially horizontally on a first one of its substantially parallel surfaces. A log guide, having a guide edge, is attached to the log. The guide edge is positioned in contact with a fence. The log is then moved substantially horizontally to a cutter for processing of the log as the guide edge is held in contact with the fence.
To ensure proper attachment of the log guide to the log, the centerlines of the log guide and the log are marked. The marked centerlines are then aligned with one another when the log guide is attached to the log.